How Much Power Does a 350 Watt Solar Panel Produce?

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The standard solar panel size nowadays is 300 watts, but larger modules like 350 watts are catching on. Not surprising given the low prices and their efficiency. But how much power can this solar panel really generate?

A 350 watt solar panel can produce 2100 watts a day or 6.3 kilowatts a month. This figure is based on the assumption there are 6 hours of sunlight per day, so shorter daylight hours will reduce the daily output.

Calculate 350 Watt Solar Panel Power Production

If you have used solar power before, you probably have an idea of the answer. If not, this guide will explain the process step by step.

In ideal weather, a 350 watt solar array will generate 350 watts an hour. With a quality system like the Renogy Flexible Solar Kit a high output should beexpected. But cloudy skies and other variables might reduce the output to 320 watts or lower.

Assuming the conditions are perfect and there are 6 hours of sunlight:

350 x 7 = 2450

You get 2100 watts a day or 73500 watts or about 7.5 kw a month.

But there are a lot of assumptions here. To get 2100 watts a day, the panel must produce 350 watts every hour. To generate 7.5 kw the panel must maintain this output for 30 days.

That is almost impossible because the weather changes several times a day, what more a month. So when calculating solar panel power, it is better to assume 85% to 95% of its output capacity.

If the solar panel reaches 350 watts two hours a day, we can assume an average of 297 to 315 watts for 5 hours, or whatever number of sunlight hours are available in your location.

So let us say the solar panel has an average output of 315 watts or 90% of its peak rating. There are 6 hours of sunlight per day.

315 x 6 = 1890

1890 x 30 = 56700

A 350 watt solar panel produces 1890 watts a day and 56700 watts / 56.7 kilowatts a month.

Why is My 350 Watt Solar Panel Not Working?

The following are the major factors that determine how much energy a solar panel generates. The following applies no matter the panel or array size .

Weather. There are a lot of factors we can cite, but the weather is the most important. When we speak of ideal weather conditions, that means clear skies, no clouds, no rain and the sun is high up there, striking the solar cell.

Sun hours. The number of sunlight hours available determines the total output. If the panel supplies 320 watts an hour, that is 1600 watts with 5 sun hours. With 7 sun hours available, that is 2240 watts.

The available sun hours depend on the season and your location. You might get 7 to 8 hours in Arizona during summer but only 4 hours in Seattle during winter.

This means you have to adjust your expectations depending on the season. But as long as you are familiar with the sun hours in your area you can make accurate estimates.

Efficiency. Solar panels have an efficiency rating that determines how much of the energy hitting the solar cell is converted into current. An efficiency rating of 21% or higher is ideal.

Solar panel position. Solar panels need space, but just as important is the orientation. Solar panels must face true south. In the southern hemisphere the solar panel has to face true north.

These factors all come into play for any solar panel. A combination of clear skies, high efficiency and proper solar panel orientation is going to be the key.

What Can a 350 Watt Solar Panel Run?

A 350 watt solar panel can run any load up to 350 watts. This assumes the solar panel is generating 350 watts. if the system is only producing 300 watts, that is all the load it can handle.

As we have pointed out, solar panel production will change throughout the day. By how much depends on the prevailing weather condition. During summer you can expect the output to be at least 300 watts, maybe 315.

Keep that in mind when deciding how much power to load. By keeping the load under 350 watts, you can be confident the system will keep running even if the output drops.

This is just an example. Depending on where you live, the output may only drop 300 watts. Or it might go down to 288 watts or lower. If you keep the load down, you do not have to worry about your appliance suddenly stopping due to lack of power.

How Long Will a 350 Watt Solar Panel Last?

Solar panels depend on sunlight. As long as the sun is out, PV modules will keep generating power. If there are 6 sun hours, the solar panel will last for 6 hours. But the output will vary depending on the time of day and other weather variables.

During summer the solar panel might generate 350 watts for 2 to 3 hours and drop to 310 or so for the rest of the day. The average output could be 315 watts an hour.

If the solar panel is powering a 300 watt load, it will keep running despite the fluctuations. It will only cease when the sun sets and the panel no longer receives any power.

But the solar panel will not work if the load is higher than its output. Remember the output drops to 310 watts during the afternoon. If the load is greater than 310 the load will stop running until the output goes up to at least 310 watts.

If the solar power load is at 350 watts, it will only run for 2 to 3 hours. So if you want to run a full load for 5 hours, you must get a larger solar array.

How Many Batteries Do I Need for a 350 Watt Solar Panel?

Another solution is to get a battery bank. Use the solar panel to charge the battery and run your power load from it. By using the battery, you can run the load without worrying about the power fluctuations.

A 350 watt solar panel should have a 50ah-100ah battery at the minimum. The battery must be at least equal to the load you want to run. With the Mighty Max 100ah AGM you can carry a significant appliance load even when the sun sets.

The more batteries you have, the longer you can keep that load running. Keep in mind that lead acid batteries have to be recharged at 50%. If you want or need more amps, get a battery with twice the capacity you need.

Is a 350 Watt Solar Panel For You?

So the question now is, is it worth getting a 350W solar panel kit? Or should you settle for a 300W or even a 320W system?

The price difference between the two varies depending where you buy. Most 350W solar panels are sold in kits with various accessories and this determines the cost.

350 watts generate more power but costs more. It really depends on how many you want to install. Some things to consider:

  • If you have an RV, a 350W solar panel is the better option. Roof
  • is limited so you should get the maximum output possible. Do keep in mind that these solar panels might put more weight on your RV’s roof though.
  • For houses, a 350W solar array is certainly going to provide more power than 300W. However these panels will be heavier and require thicker cables.
  • You also have to consider the other items in the kit. A typical solar panel kit includes the PV modules, charge controller and all the required connectors and hardware.

A complete kit is ideal for beginners. Note that there are different types of kits, and the more components included, the costlier. The easiest way to handle this is to contact a solar installer and have them do the installation for you.

If you want to do it yourself, buy a kit from a reputable manufacturer. You can also buy the parts separately to get the set up you want. But make sure that the components are compatible with each other.


Just like with any solar panel, a 350W PV module depends on several factors to produce maximum output. With the right setup and favorable conditions, this is a good choice for a residential solar array or an RV solar system.